A dishwasher filling with water when it’s not being used typically means that dishwasher repairs are imminent, but the severity of the issue may not be immediately obvious. The problem could be as simple as a minor drain clog or a kinked drain hose, or it could be something more extreme such as a leak in the water supply line. Common causes of water in the bottom of a dishwasher include a backflow caused by a kink in the drain hose, a malfunctioning check valve in the dishwasher’s drain system, a broken or worn out inlet valve, a leaking water supply line, a faulty drain pump, and a clog in the drain line. Steps to take to confirm if the drain is clogged include removing the pooled water from the dishwasher, checking the bottom of the dishwasher for debris and ensuring the drain is clear, cleaning the dishwasher filter, checking the drain hose to ensure the hose isn’t blocked, and running an empty dishwasher cycle. There are steps a homeowner can take to troubleshoot the issue, however, most repairs should be completed by a licensed plumber or appliance repair technician.